Wikipedia:Verifiability: Difference between revisions

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{{nutshell|Readers must be able to check that any of the information within Wikipedia articles is not just made up. This means all material must be attributable to reliable, published sources. Additionally, quotations and any material challenged or likely to be challenged must be supported by [[WP:INCITE|inline citations]].}}

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In the [[English Wikipedia]], '''verifiability''' means other people using the encyclopedia can check that the information comes from a [[Wikipedia:Reliable sources|reliable source]]. Its content is determined by previously published information rather than editors' beliefs, opinions, experiences, or [[Wikipedia:No original research|previously unpublished ideas or information]]. Even if you are sure something is true, it must have been previously published in a reliable source before you can add it.{{efn|This principle was previously expressed on this policy page as "the threshold for inclusion is '''verifiability, not truth'''". See the essay, [[Wikipedia:Verifiability, not truth]].}} If reliable sources disagree with each other, then maintain a [[Wikipedia:Neutral point of view|neutral point of view]] and present what the various sources say, giving each side its [[Wikipedia:Neutral point of view#Undue weight|due weight]].

 

 

For how to write citations, see [[Wikipedia:Citing sources|citing sources]]. Verifiability, [[Wikipedia:No original research|no original research]], and [[Wikipedia:Neutral point of view|neutral point of view]] are Wikipedia's core content policies. They work together to determine content, so editors should understand the key points of all three. Articles must also comply with the [[Wikipedia:Copyrights|copyright policy]].

 

==Responsibility for providing citations<span class="anchor" id="Burden"></span><span class="anchor" id="Burden of evidence"></span>==

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{{See also|Wikipedia:Editing policy#Try to fix problems}}

 

 

 

The cited source must clearly support the material as presented in the article. Cite the source clearly, ideally giving page number(s)&mdash;though sometimes a section, chapter, or other division may be appropriate instead; see [[Wikipedia:Citing sources]] for details of how to do this.

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===What counts as a reliable source===

===Newspaper and magazine blogs===

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===Reliable sources noticeboard and guideline<span id="Reliable sources noticeboard and WP:IRS guideline"></span>===

===Exceptional claims require exceptional sources===

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Any exceptional claim requires {{em|multiple}} high-quality sources.<ref>[[David Hume|Hume, David]]. [https://books.google.com/books?id=H1rKYw9SnTgC&lpg=PP1&pg=PA86 ''An Enquiry concerning Human Understanding''], Forgotten Books, 1984, pp. 82, 86; first published in 1748 as ''Philosophical enquiries concerning human Understanding'', (or the Oxford 1894 edition {{OL|7067396M}} at para. 91) "A wise man{{nbsp}}... proportions his belief to the evidence{{nbsp}}... That no testimony is sufficient to establish a miracle, unless the testimony is of such a kind, that its falsehood would be more miraculous, than the fact, which it endeavors to establish; and even in that case there is a mutual destruction of arguments, and the superior only gives us an assurance suitable to that degree of force, which remains, after deducting the inferior." In the 18th century, [[Pierre-Simon Laplace]] reformulated the idea as "The weight of evidence for an extraordinary claim must be proportioned to its strangeness." [[Marcello Truzzi]] recast it again, in 1978, as "An extraordinary claim requires extraordinary proof." [[Carl Sagan]], finally, popularized the concept broadly as "Extraordinary claims require extraordinary evidence" in 1980 on ''[[Cosmos: A Personal Voyage]]''; this was the formulation originally used on Wikipedia.</ref> [[Red flag (idiom)|Warnings (red flags)]] that should prompt extra caution include:

* Surprising or apparently important claims not covered by multiple mainstream sources;